#include <stdio.h>
#include <string.h>
#include <stdlib.h>

	int a;
	int b;
	double ans;

double C(int y, int x)
{
	double r=1.0;
	int i, k;
	for (i=1, k=y; i<=x; i++, k--)
	{
		r = r * (double) k / (double) i;
	}
	return r;
}

main()
{
	double c13a, c13b, c26ab;
	while (scanf("%d%d", &a, &b), a>=0)
	{
		c13a = C(13, a);
		c13b = C(13, b);
		c26ab = C(26, a+b);
		ans = c13a*c13b/c26ab;
		if (a!=b) ans*=2;
		printf("%d-%d split: %0.8lf\n", a, b, ans);
	}
	return 0;
}

